<?php
################################################################################### 
# XML_serialize: serializes any PHP data structure into XML 
# Takes one parameter: the data to serialize. Must be an array. 
################################################################################### 

################################################################################### 
# XML class: utility class to be used with PHP's XML handling functions 
################################################################################### 
class xml
{
    var $parser; #a reference to the XML parser
    var $document; #the entire XML structure built up so far
    var $parent; #a pointer to the current parent - the parent will be an array
    var $stack; #a stack of the most recent parent at each nesting level
    var $last_opened_tag; #keeps track of the last tag opened.

    function xml()
    {
        $this->parser = & xml_parser_create();
        xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, false);
        xml_set_object($this->parser, $this);
        xml_set_element_handler($this->parser, 'open', 'close');
        xml_set_character_data_handler($this->parser, 'data');
    }

    function destruct()
    {
        xml_parser_free($this->parser);
    }

    function & parse(&$data)
    {
        $this->document = array();
        $this->stack = array();
        $this->parent = & $this->document;
        return xml_parse($this->parser, $data, true) ? $this->document : NULL;
    }

    function open(&$parser, $tag, $attributes)
    {
        $this->data = ''; #stores temporary cdata
        $this->last_opened_tag = $tag;
        if (is_array($this->parent) and array_key_exists($tag, $this->parent)) { #if you've seen this tag before
            if (is_array($this->parent[$tag]) and array_key_exists(0, $this->parent[$tag])) { #if the keys are numeric
                #this is the third or later instance of $tag we've come across
                $key = count_numeric_items($this->parent[$tag]);
            } else {
                #this is the second instance of $tag that we've seen. shift around
                if (array_key_exists("$tag attr", $this->parent)) {
                    $arr = array('0 attr' => &$this->parent["$tag attr"], &$this->parent[$tag]);
                    unset($this->parent["$tag attr"]);
                } else {
                    $arr = array(&$this->parent[$tag]);
                }
                $this->parent[$tag] = & $arr;
                $key = 1;
            }
            $this->parent = & $this->parent[$tag];
        } else {
            $key = $tag;
        }
        if ($attributes) $this->parent["$key attr"] = $attributes;
        $this->parent = & $this->parent[$key];
        $this->stack[] = & $this->parent;
    }

    function data(&$parser, $data)
    {
        if ($this->last_opened_tag != NULL) #you don't need to store whitespace in between tags
            $this->data .= $data;
    }

    function close(&$parser, $tag)
    {
        if ($this->last_opened_tag == $tag) {
            $this->parent = $this->data;
            $this->last_opened_tag = NULL;
        }
        array_pop($this->stack);
        if ($this->stack) $this->parent = & $this->stack[count($this->stack) - 1];
    }
}
function count_numeric_items(&$array)
{
    return is_array($array) ? count(array_filter(array_keys($array), 'is_numeric')) : 0;
}

function & xml_unSerialize($xml)
{
    $xml_parser = & new xml();
    $data = & $xml_parser->parse($xml);
    $xml_parser->destruct();
    return $data;
}
?> 
